1. Technical Field
The present invention relates to a carrier plate such as is predominantly used in automobiles with automatic transmissions, as well as to a method for the production of such plates.
2. Description of The Related Art
A generic carrier plate at any rate comprises a ring gear as well as a driving plate, which is arranged on the inner circumference surface of the ring gear. Customary carrier plates furthermore have one or two thickening plates that are arranged as a covering interlayer or reinforcing plate on opposite sides of the driving plate and that are attached to this driving plate in a concentric manner. The corresponding reinforcing and/or distance plates are restricted, in the radial direction, to the central area of the driving plate and concentrically surround a centre bore hole in the carrier plates, said bore hole forming a hub for the crankshaft.
A corresponding carrier plate is described, for example, in DE 199 05 713 C1. An alternative example is disclosed in DE 32 36 321 D2.
The carrier plate serves to transmit the moment between the crankshaft of the combustion engine and the torque converter in the case of motor vehicles with automatic transmissions. The ring gear mounted on the driving plate increases the torque of the starter motor and transfers this torque to the crankshaft while the engine is being started.
The connection between the ring gear and the driving plate can be brought about by means of various methods. For example, the parts can be welded together (cf. DE 199 05 713 C1). The at least one thickening plate provided in a central part of the driving plate stiffens, on the one hand, the driving plate, so that this plate can better absorb a flexural type stress. The at least one thickening plate furthermore reinforces bore holes provided concentrically to the hub, whereby these bore holes are also provided on the driving plate, and whereby the carrier plate can be screwed to the crankshaft through these bore holes. The axial position of the carrier plate between the crankshaft and the torque converter is furthermore determined by the at least one thickening plate. The at least one thickening plate does not transfer any relevant torques, so that there are various possibilities for connecting the at least one thickening plate to the driving plate. For example, it is known to weld the thickening plate to the driving plate (DE 199 05 713). The at least one thickening plate can just as well be connected to the driving plate by means of clinching, rivets or even gluing. It is only necessary for the connection to be provided in such a way that the carrier plate is attached to the crankshaft in the area of the gearbox by means of screwing until the time of the final assembly. After that time the crankshaft screws take over the attachment of the at least one thickening plate.
DE 199 05 713 C1 describes a method in which all components of the carrier plate are connected to one another in a metal inert gas welding (MIG) or metal active gas welding (MAG) procedure. The corresponding MIG or MAG welding methods lead, however, to a high level of heat being introduced into the workpiece, which can warp as a result. There is also the problem that weld spatter can blemish the surface of the workpiece. The MIG or MAG welding procedure correspondingly makes touch up steps necessary. It is furthermore necessary to specially prepare that at least one thickening plate for the weld seam.
The basis of the following invention is formed by the problem of specifying a carrier plate and a method for its production that lead to an improvement in the quality and profitability of the production of the carrier plate.